Pesticides in surface water from Brazil and Paraguay cross-border region: Screening using LC-QTOF MS and correlation with land use and occupation through multivariate analysis

Abstract

In this study, the presence of pesticides in surface water from Brazil and Paraguay cross-border region was investigated by application of screening method based on Liquid Chromatography coupled to Quadrupole-Time of Flight mass spectrometry (LC-QTOF MS). The main results indicated screening of 43 pesticides from different classes, being herbicide, fungicide, and insecticide the most tentatively identified classes. From these 43 compounds, 36 were tentatively identified in rivers located in Brazil and 28 in rivers located in Paraguay. The most frequently detected compounds were atrazine and its metabolites (desethylatrazine (DEA), 2-hydroxy-atrazine and desisopropylatrazine (DIA)) and, also dinoterb and 8-hydroxyquinoline. Screening data and land use were subjected to cluster analysis (CA) and the 24 monitoring sites were classified from relatively low pollution to high pollution. Principal Component Analysis (PCA) was carried out a multivariate exploratory investigation of pesticides data and their relationship with land use. Open access software was used to predict in silico persistence and toxicity of the compounds, being fipronil TPs and difeconazole present the highest persistence time.